Recessed and embedded die coreless package

ABSTRACT

Methods of forming a microelectronic packaging structure and associated structures formed thereby are described. Those methods may include forming a cavity in a plating material to hold a die, attaching the die in the cavity, forming a dielectric material adjacent the die, forming vias in the dielectric material adjacent the die, forming PoP lands in the vias, forming interconnects in the vias, and then removing the plating material to expose the PoP lands and die, wherein the die is disposed above the PoP lands.

RELATED APPLICATIONS

The present application is a Divisional of U.S. application Ser. No.12/655,321 filed Dec. 29, 2009, entitled “RECESSED AND EMBEDDED DIECORELESS PACKAGE”.

BACKGROUND OF THE INVENTION

As semiconductor technology advances for higher processor performance,advances in packaging architectures may include package-on-package (PoP)architecture and other such assemblies. As the design of packagestructures becomes more complex, there is often a resulting increase inassembly expense. Thus there is a need to significantly lower packageand assembly costs for advanced package structures.

BRIEF DESCRIPTION OF THE DRAWINGS

While the specification concludes with claims particularly pointing outand distinctly claiming certain embodiments of the present invention,the advantages of this invention can be more readily ascertained fromthe following description of the invention when read in conjunction withthe accompanying drawings in which:

FIGS. 1 a-1 m represent methods of forming structures according to anembodiment of the present invention.

FIG. 2 represents a system according to an embodiment of the invention.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

In the following detailed description, reference is made to theaccompanying drawings that show, by way of illustration, specificembodiments in which the invention may be practiced. These embodimentsare described in sufficient detail to enable those skilled in the art topractice the invention. It is to be understood that the variousembodiments of the invention, although different, are not necessarilymutually exclusive. For example, a particular feature, structure, orcharacteristic described herein, in connection with one embodiment, maybe implemented within other embodiments without departing from thespirit and scope of the invention. In addition, it is to be understoodthat the location or arrangement of individual elements within eachdisclosed embodiment may be modified without departing from the spiritand scope of the invention. The following detailed description is,therefore, not to be taken in a limiting sense, and the scope of thepresent invention is defined only by the appended claims, appropriatelyinterpreted, along with the full range of equivalents to which theclaims are entitled. In the drawings, like numerals refer to the same orsimilar functionality throughout the several views.

Methods and associated structures of forming and utilizing amicroelectronic structure, such as a package structure, are described.Those methods may comprise forming a cavity in a plating material tohold a die, attaching the die in the cavity, forming a dielectricmaterial adjacent to the die, forming vias in the dielectric materialadjacent the die, forming PoP lands in the vias, forming interconnectsin the vias, and then removing the plating material to expose the PoPlands and die. Methods of the present invention enable the fabricationof package-on-package architectures such as PoP assemblies comprisingpartially recessed and/or fully embedded die or any other type of ballgrid array (BGA) package.

FIGS. 1 a-1 m illustrate embodiments of a method of forming amicroelectronic structure, such as a package structure, for example.FIG. 1 a illustrates a material 100. In one embodiment, the material 100may comprise a plating material, such as but not limited to a copperfoil plating material, for example. In some embodiments, any suitableplating material may be utilized, depending upon the particularapplication. In FIG. 1 b, a cavity 102 may be formed in the material100. The cavity 102 may be formed utilizing any suitable etching processin some embodiments, such as are known in the art. In an embodiment, thecavity 102 may be formed such that the cavity 102 may hold a die, suchas a microelectronic die, for example. The cavity 102 may comprise abottom portion 101 an angled portion 103, and a top portion 105. In anembodiment, the bottom and top portions may be separated by a barrierlayer to aid in the formation of the cavity structure, especially for anetching process. In an embodiment (not shown), PoP land structures (tobe described further herein) can be formed on surface 101.

In an embodiment, a die 104 may be attached within the cavity 102 (FIG.1 c). In an embodiment, the die 104 may comprise a thin die 104, and maycomprise a thickness of below about 150 microns. In an embodiment, thedie 104 may be attached to the top portion 105 of the cavity 101. In anembodiment, the die 104 may comprise at least one sidewall 106, a topside 107 and a bottom/active side 108. In some cases, an adhesive filmand/or an attach process may be used to attach the die 104 into thecavity 102 of the plating material 100. In an embodiment, the adhesivefilm (not shown), can be used as a permanent part of a final package toprotect the die backside, to provide a surface for marking, and/ormanage any warpage that may occur within the die 104, for example.

A dielectric material 110 may be formed on the plating material 100 andadjacent the die 104 that is in the cavity 102 of the plating material100 (FIG. 1 d). In an embodiment, the dielectric material 110 may beformed by a laminating process, for example. The dielectric material 110may be formed on the bottom portion 101 of the cavity 102, on the angledportion 103 of the cavity 102, and on a portion of the top portion 105of the cavity 102 of the plating material 100 that surrounds the die104. Vias 112 may be formed in a region 114 of the dielectric material110 adjacent the die 104 (FIG. 1 e). In an embodiment, a package onpackage (PoP) land area 113 may be formed within the via 112, wherein aportion of the plating material 100 may be removed to form the PoP landarea 113. In an embodiment, the plating material 100 and the dielectricmaterial 110 may be removed using any suitable etching process.

In an embodiment, a PoP land structure 116 may be formed in the PoP landarea 113 (FIG. 1 f). The PoP land structure 116 may be formed in the PoPland area 113 by using an electrolytic plating process, for example,however any suitable process may be utilized to form the PoP landstructure 116. In an embodiment, the plating material 100 within the PoPland area 113 may be used as a plating bus for the formation of the PoPland structure 116. In an embodiment, the plating material 100 maycomprise a copper foil that may be used as a plating bus. In some cases,plating metallurgies may include gold, nickel, gold/nickel,gold/nickel/palladium, and the similar suitable materials, according tothe particular application. In an embodiment, wire bond pads may beplated on the PoP land area 113, allowing for a mixed-technologystacking on a CPU die backside, for example.

In an embodiment, vias 118 may be formed in a die area 119, wherein diepads, for example copper die pads, maybe exposed on the active side 108of the die 104 (FIG. 1 g). The vias 112 adjacent the PoP land structures116 (those located in the dielectric region 114) and the vias 118 in thedie area 119 may be plated with a metallic material (FIG. 1 h) to formPoP land structure 116 interconnect structures 117 and to form die padinterconnect structures 120. In an embodiment, the PoP land interconnectstructure 117 may be electrically connected to the PoP land structure116, and the die pad interconnect structure 120 may be electricallyconnected to die pads on the active side 108 of the die 104.

In an embodiment, a semi-additive process (SAP) may be used to form thedie pad interconnect structures 120 and the PoP interconnect structures118. In some embodiments, the die pad interconnect structures 120 andthe PoP interconnect structures 118 may be formed in the same processstep, or in other embodiments, the die pad interconnect structures 120and the PoP interconnect structures 118 may be formed in separateformation steps. A second dielectric layer 110′ may be formed on the diepad interconnect structures 120 and the PoP interconnect structures 118(FIG. 1 i). A first metallization layer 121 may be formed in the seconddielectric layer 110′.

Subsequent layers may then be formed using standard substrate SAPbuild-up processing, for example, wherein further dielectric layers 120″and metallization layers 121′ may be formed upon each other to form acoreless substrate 125 by utilizing a buildup process (FIG. 1 j). Theplating material 100 may then be removed from the die 104 and the PoPland structures 116 of the coreless substrate 125, exposing the PoPlands and the die, to form a coreless package structure 126 (FIG. 1 k).The coreless package structure 126 may comprise a fillet structure 127of dielectric material 110 around the die 104, wherein the dielectricmaterial 110 may surround the sidewall 106 and the bottom 108 of the die104, but wherein the dielectric material 110 is absent on the top side107 of the die 104.

The fillet structure 127 may comprise a portion of the dielectric 110that may be angled/raised in relation to a planar top portion 111 of thedielectric 110 of the coreless substrate 125. The geometry of thisfillet structure 127 can be optimized to provide maximum reliability ofthe die/package, wherein an angle 128 of the fillet structure 127 may bevaried to optimize reliability. In an embodiment, the angle of thefillet structure may comprise about 70 degrees or less, but may bevaried according to the application.

In an embodiment, the coreless package structure 126 may comprise thedie 104 being at least partially embedded in the coreless substrate 125.In other embodiments, the coreless package structure 126 may comprisethe die 104 being substantially entirely embedded in the corelesssubstrate 125. In some embodiments, the top side 107 of the die 104 maybe substantially coplanar with the top portion 111 of the dielectric110. In another embodiment, there may be a distance 129 between the topside 107 of the die 104 and a top side 131 of the PoP land 116.

The coreless package structure 126 may comprise package interconnectstructures areas 122, wherein interconnect structures 124, such as ballgird array (BGA) balls, may be attached (FIG. 1 l). The PoP landstructures 116 of the coreless package structure 126 may compriseraised, electrolytically plated lands 116 disposed on top of thecoreless substrate 125, thus enabling the attachment of another packageon top of the coreless package structure 126 (e.g. Package-on-Packagestructure).

FIG. 1 m depicts a PoP structure 130, wherein a second package 132 isconnected to the coreless package structure 126 by attachment to the PoPland structures 116. In an embodiment, the second package 132 maycomprise a die 104′ that is directly above the die 104 of the corelesspackage structure 126. Interconnect balls 124′ of the second package 132may be attached to the PoP land structures 116 of the coreless packagestructure 126.

FIG. 2 is a diagram illustrating an exemplary system 200 capable ofbeing operated with methods for fabricating a microelectronic structure,such as the coreless package structure 126 of FIG. 1 l, for example. Itwill be understood that the present embodiment is but one of manypossible systems in which the coreless package structures of the presentinvention may be used.

FIG. 2 shows a computer system according to an embodiment of theinvention. System 200 includes a processor 210, a memory device 220, amemory controller 230, a graphics controller 240, an input and output(I/O) controller 250, a display 252, a keyboard 254, a pointing device256, a peripheral device 258, and a bus 260. Processor 210 may be ageneral purpose processor or an application specific integrated circuit(ASIC). I/O controller 250 may include a communication module for wiredor wireless communication. Memory device 220 may be a dynamic randomaccess memory (DRAM) device, a static random access memory (SRAM)device, a flash memory device, or a combination of these memory devices.Thus, in some embodiments, memory device 220 in system 200 does not haveto include a DRAM device.

One or more of the components shown in system 200 may be included in oneor more integrated circuit packages, such as the coreless packagestructure 126 of FIG. 1 l for example. For example, processor 210, ormemory device 220, or at least a portion of I/O controller 250, or acombination of these components may be included in an integrated circuitpackage that includes at least one embodiment of a structure describedin FIGS. 1 a-1 m.

System 200 may include computers (e.g., desktops, laptops, hand-helds,servers, Web appliances, routers, etc.), wireless communication devices(e.g., cellular phones, cordless phones, pagers, personal digitalassistants, etc.), computer-related peripherals (e.g., printers,scanners, monitors, etc.), entertainment devices (e.g., televisions,radios, stereos, tape and compact disc players, video cassetterecorders, camcorders, digital cameras, MP3 (Motion Picture ExpertsGroup, Audio Layer 3) players, video games, watches, etc.), and thelike.

Benefits of the present invention enable a new packaging architecturethat can meet design requirements for future mobile/handheld system on achip (SoC) processors at roughly half the cost of current packagearchitectures. Embodiments provide a method of embedding a die in asubstrate, which enables the elimination of many assembly processes.Embodiments enable thin die assembly, PoP compatibility, substratedesign rule scalability, package thickness reduction, andpackage/assembly cost reduction. In addition, the substrate is no longerconfined to strip manufacturing capability, which enables full panelprocessing, which also reduces costs.

Although the foregoing description has specified certain steps andmaterials that may be used in the method of the present invention, thoseskilled in the art will appreciate that many modifications andsubstitutions may be made. Accordingly, it is intended that all suchmodifications, alterations, substitutions and additions be considered tofall within the spirit and scope of the invention as defined by theappended claims. In addition, it is appreciated that variousmicroelectronic structures, such as package structures, are well knownin the art. Therefore, the Figures provided herein illustrate onlyportions of an exemplary microelectronic device that pertains to thepractice of the present invention. Thus the present invention is notlimited to the structures described herein.

What is claimed is:
 1. A method comprising; forming a cavity in aplating material; attaching a die in the cavity; forming a dielectricmaterial adjacent the die and over the plating material; forming viasthrough the dielectric material in a region of the dielectric materialadjacent the die; forming package-on-package land areas in the platingmaterial by removing a portion of the plating material within the vias;forming package-on-package land structures in the package-on-packageland areas; forming vias through the dielectric material in the die areato expose die pads on the die; forming die pad interconnect structuresin the die area vias and forming package-on-package interconnectstructures in the dielectric region vias; and removing the platingmaterial to expose the die and the package-on-package land structures.2. The method of claim 1 further comprising forming subsequent metallayers on the die pad interconnect structures and on thepackage-on-package interconnect structures to form a coreless substrate.3. The method of claim 2 further comprising wherein the die is partiallyembedded into the coreless substrate, and wherein the dielectricmaterial is formed along a portion of a sidewall of the die.
 4. Themethod of claim 2 further comprising wherein the die is substantiallyfully embedded into the coreless substrate, and wherein the dielectricmaterial is formed along a portion of a sidewall of the die.
 5. Themethod of claim 2 further comprising wherein the package-on-package landstructures comprise raised, electrolytically plated lands on top of thecoreless package.
 6. The method of claim 1 further comprising wherein aportion of the dielectric material comprises a fillet structuresurrounding a portion of the sidewall of the die.
 7. The method of claim6 further comprising wherein an angle is between a raised portion of thefillet structure and a planar top portion of the dielectric material. 8.The method of claim 1 further comprising wherein interconnect structuresof a second package are attached to the package-on-package landstructures.
 9. A method comprising; forming a cavity in a platingmaterial to hold a die; attaching the die in the cavity; forming adielectric material adjacent the die and over the plating material;forming vias through the dielectric material in the dielectric materialadjacent the die; forming package-on-package land areas in the platingmaterial by removing a portion of the plating in the vias; formingpackage-on-package lands in the package-on-package land areas; forminginterconnects in the vias; and removing the plating material to exposethe package-on-package lands and die, wherein the die is disposed abovethe package-on-package lands.
 10. The method of claim 9 furthercomprising wherein the die is attached using an adhesive film.
 11. Themethod of claim 9 further comprising wherein the plating materialcomprises an electroplating metal.
 12. The method of claim 11 whereinforming the package-on-package lands in the vias further comprisesforming wire bond pads in the vias.
 13. The method of claim 9 furthercomprising wherein forming the package-on-package lands in the viascomprises using the plating material as the plating bus to form thepackage-on-package lands.
 14. The method of claim 9 further comprising:forming vias in a die area, exposing pads on the die; and plating thevias in the die area.
 15. The method of claim 14 further comprisingwherein a coreless substrate is built up on the package-on-package landsand on the plated die vias.